Gardening Columns

Get Growing with Greens

First published on garden.org on March 15, 2007, by Suzanne DeJohn

Few vegetables are as easy to grow, nutritious, and fast-maturing as salad greens. These reasons alone make them perfect for novice gardeners and a must for more seasoned growers. Last year's spinach scare over contaminated California produce is a distant memory to many, but it does underscore the inherent benefits of growing your own. However, there's another reason that might just tip the balance in favor of homegrown greens.

According to the nonprofit Environmental Working Group (EWG, http://www.ewg.org), spinach and lettuce are among the so-called Dirty Dozen -- the twelve fruits and vegetables that expose consumers to the most pesticide residue. The Dirty Dozen are peaches, apples, sweet bell peppers, celery, nectarines, strawberries, cherries, pears, grapes (imported), spinach, lettuce, and potatoes. EWG recommends opting for organically grown when it comes to these produce items.

How did EWG come up with the ranking? They pored over the results of nearly 43,000 tests for pesticides on produce collected by the U.S. Department of Agriculture and the U.S. Food and Drug Administration between 2000 and 2004. Taking into consideration how people typically eat their produce (peeled banana vs. unpeeled apple), they created the Shoppers Guide to Pesticides in Produce, which informs consumers so they can make choices that lower pesticide exposure in their diets.

Growing Your Own
Homegrown produce is ideal since you know how it's been handled, but of the twelve fruits and vegetables on the list, some are easier to grow than others. Peach, apple, nectarine, cherry, and pear trees, as well as grapevines, require a fair amount of space and commitment. Celery is challenging to grow in the home garden. But peppers, strawberries, spinach, lettuce, and potatoes are good candidates, and of these spinach and lettuce are the easiest to grow.

Start with Spinach
Spinach is a cool-season crop that can withstand hard frosts and temperatures as low as 20 degrees F. It grows best when there's less than 14 hours of daylight per day and temperatures don't exceed 80 degrees F. Long days and hot weather cause spinach to send up flower stalks, called bolting, which ends the harvest. Sow seeds directly in the garden now, and continue to sow every week until late spring for an extended harvest. For later plantings choose varieties described as "long-standing" or "slow to bolt."

Lettuce Later
Lettuce plants are relatively cold tolerant, but the seeds germinate best in warm soil. In the warmer parts of our region you can direct sow now. In the cooler mountains you have two options: Start seeds indoors now, let them grow for a month or so, harden them off, and plant them out as transplants; or wait several weeks to direct sow. Leaf lettuces, as opposed to head lettuces such as iceberg, are the best choice for the home garden.

Preparing the Bed
A fertile, sandy loam high in organic matter is ideal for growing salad greens. Most lettuces prefer a soil pH of 6 to 6.5; spinach grows best in slightly "sweeter" soil with a pH between 6.4 and 6.8. A soil test is a good investment (especially in Arkansas and North Carolina, where it's free). (Visit http://garden.org/regional/report/arch/gv/2299 for the location of soil-testing labs and soil test prices.) If necessary use lime to raise the pH of acid soils; if the soil test shows a deficiency of magnesium, use dolomitic lime. Note that lime takes a while to dissolve and so it may not change the pH much for this spring's planting.

A 3- to 4-foot-wide raised bed is ideal. Raised beds warm up quickly in spring, drain well, make efficient use of space, and allow you to harvest from both sides without stepping in the bed. Amend soil with lots of compost. If you use cow or horse manure in your compost, make sure the compost has aged for at least six months and preferably a year before using, just to be on the safe side. Work the compost into the top 8 inches of soil, then rake the seedbed flat and you're ready to sow.

Sowing Seeds
For an extended season, sow a small patch of greens every few weeks so the supply will continue until the weather gets too warm and they bolt. Then you can use the bed for warm-season greens, such as Malabar spinach. Follow the instructions on the seed packet for planting depth, spacing, and thinning seedlings.

You can sow more densely than suggested if you plan to harvest baby greens. Veteran gardeners who can distinguish weed from crop seedlings can simply broadcast seeds over the bed. Otherwise, sow in rows.

Wildly expensive in stores, baby greens are remarkably tender, succulent, and mild. You can begin harvesting greens when plants are 2 inches tall. Use clean scissors to cut the largest leaves, or shear the whole bed down to about an inch above the soil line. Spinach and most leaf lettuces are "cut and come again" crops, meaning they'll regrow as long as you haven't damaged their crowns -- the area just above the soil line where the leaves emerge. Some connoisseurs find baby spinach and leaf lettuce lacking in flavor and prefer to wait until the crops are a bit more mature. It's up to you.

Expand Your Palette
An added benefit of growing your own greens is that you can sample types hard to find in grocery stores, such as arugula, mizuna, mustard greens, tat-soi, and radicchio. Or try mesclun, which is a mix of different types of greens. Some mesclun mixes are heavier on spicy greens, some on more mild ones, so choose a mix that suits you. Although most of us eat our collards, chard, kale, and beet greens cooked, these are good for summer-long harvests of baby greens.

According to the Shoppers Guide to Pesticides in Produce, the 12 produce items with the least amount of pesticides are onions, avocados, frozen sweet corn, pineapples, mangoes, asparagus, frozen peas, kiwis, bananas, cabbage, broccoli, and papayas. But don't let that stop you from planting asparagus, corn, onions, and peas in your home garden. Homegrown will almost always top storebought.